Every Qt application I've ever used has been ... off.

Granted, it's closer than Swing. That's a pretty low bar. We need to either start qualifying this ("it's a good GUI toolkit for a cross-platform one"), or accepting that this is a scale (10 is "actually native", 0 is "just looks like Motif everywhere"). I'd give Qt 8/10 -- it's pretty good, and the screenshots look great but after a moment using it I'll say "wait, I think I know why everything feels just a little bit off".